WASHINGTON, D.C.—In a tweet Wednesday afternoon, June 13, President Trump backed GOP Senate hopeful Kevin Cramer, reaffirming his support after he officially endorsed him back in March. The tweet comes as anticipation ramps up for what is expected to be a hotly contested race with incumbent Sen. Heidi Heitkamp, D-N.D., in November’s general election.

The tweet from President Trump reads: "Congratulations to @kevincramer on his huge win in North Dakota. We need Kevin in the Senate, and I strongly endorse him. Heidi voted NO on our Tax Cuts, and always will vote no when we need her. Kevin is strong on Crime & Borders, big on Cutting Taxes!"

Trump’s tweet comes one day after both Cramer and Heitkamp won their respective North Dakota primary elections. Heitkamp, the Democratic incumbent seeking a second term, ran unopposed.

Meanwhile, Cramer, a Republican, ran away with an easy victory over his lone opponent, Thomas O’Neill, of Niagra. Cramer won the primary collecting 87.5 percent of the vote, compared to 12 percent for O’Neill.

Julie Krieger, communications director for the Heitkamp campaign, responded to the tweet in an email to Forum Communications.

“After weeks of headlines on Heidi’s proven ability to put politics aside and achieve results for North Dakota through a productive relationship with the president, it’s no surprise that Congressman Cramer needed a lifeline reminder of an announcement made back in March,” Krieger wrote. “Heidi’s focus will remain not on pleasing whoever is in the White House, but standing up for North Dakotans.”

Trump’s endorsement of Cramer comes just days after the GOP Senate hopeful sat down in an interview with the Washington Post. In the report, Cramer blasted the Trump administration, saying that he believed Trump was giving Heitkamp preferential treatment because she is a woman.

Prior to Wednesday’s tweet, Trump was aggressive in his attacks on the GOP’s Democratic Senate rivals, with Heitkamp being the lone exception. Until Wednesday.

Historically, Heitkamp has been one of a handful of Democrats willing to vote across party lines. Heitkamp was the only Democratic lawmaker at a May 24 White House event in which Trump signed a bill easing restrictions on banks, a measure which she co-sponsored.

At the bill signing, Heitkamp stood directly to Trump’s left, while Cramer stood behind the President, the Washington Post reported.

“I do think there’s a little difference in that she’s a woman,” Cramer told the Washington Post. “That’s probably part of it—that she’s a, you know, a female. He doesn’t want to be that aggressive, maybe. I don’t know.”

Trump’s tweet may prove to be a blow to Heitkamp’s campaign, which to this point, has promoted and touted in advertisements her ability to vote across party lines.

In a recent Heitkamp television ad titled “Battery Acid,” a quote from Sen. Bob Corker, R-Tenn, where he calls Heitkamp “stronger than battery acid” is used as an example of that bipartisanship.

As the ad comes to an end, Heitkamp finishes with the line “when it comes to fighting for North Dakota, I take battery acid as a compliment.”